A combined field and laboratory design for assessing the impact of night shift work on police officer operational performance.

OBJECTIVES

This study assessed the utility of a combined field and laboratory research design for measuring the impact of consecutive night shift work on the sleepiness, vigilance, and driving performance of police patrol officers.

DESIGN

For police patrol officers working their normal night shift duty cycles, simulated driving performance and psychomotor vigilance were measured in a laboratory on two separate occasions: in the morning after the last of five consecutive 10.7-h night shifts, and at the same time in the morning after three consecutive days off duty. Order of participation in conditions was randomized among subjects.

SETTING

Subjects experienced manipulation of sleep schedules due to working night shifts in a real operational environment, but performance testing was conducted under controlled laboratory conditions.

PARTICIPANTS

N = 29 active-duty police patrol officers (27 male, 2 female; age 37.1 ± 6.3 years) working night shift schedules participated in this study.

RESULTS

Simulated driving performance, psychomotor vigilance, and subjective sleepiness were significantly degraded following 5 consecutive night shifts as compared to 3 consecutive days off duty, indicating that active-duty police officers are susceptible to performance degradation as a consequence of working nights.

CONCLUSIONS

This combined field and laboratory research design succeeded in bridging the gap between the realism of the operational environment and the control of laboratory performance testing, demonstrating that this is a useful approach for addressing the relationship between shift work induced fatigue and critical operational task performance.